Question: Solve for $x$ and $y$ using substitution. ${-2x+4y = -2}$ ${x = -y+4}$
Explanation: Since $x$ has already been solved for, substitute $-y+4$ for $x$ in the first equation. ${-2}{(-y+4)}{+ 4y = -2}$ Simplify and solve for $y$ $2y-8 + 4y = -2$ $6y-8 = -2$ $6y-8{+8} = -2{+8}$ $6y = 6$ $\dfrac{6y}{{6}} = \dfrac{6}{{6}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = -y+4}\thinspace$ to find $x$ ${x = -}{(1)}{ + 4}$ $x = -1 + 4$ ${x = 3}$ You can also plug ${y = 1}$ into $\thinspace {-2x+4y = -2}\thinspace$ and get the same answer for $x$ : ${-2x + 4}{(1)}{= -2}$ ${x = 3}$